The present invention relates in general to wrap around heat shrinkable closures.
Wrap around heat shrinkable closures have been described and used in the past for covering and sealing articles of various shapes, typically tubular. A wrap around heat shrinkable closure is taught in U.S. Pat. No. 4,153,747, the disclosure of which is incorporated herein. The closure described in that patent comprises a generally rectangular sheet of heat shrinkable polymer having a large central section which has been hot stretched and cooled while in stretched condition and two small, flat, unstretched end sections integral with the central section. One end section has adhesive on the upper or outer surface and the other section has adhesive on the lower or inner surface whereby the sheet can be wrapped in tubular form to bring the adhesive layers together to hold the closure in tubular form while heat is applied and the closure shrunk down on an object.
The stiff end sections make the closure difficult to manipulate, especially in smaller diameter sizes, and tend to cause the closure to peel apart at the adhesive joint and inhibit the provision of a uniform seal along the adhesive joint. Closures of this construction have been made with one end section having an extension that is positioned inside the completed closure. However, this extended rigid section interferes with the application of the closure, even when the thickness of the extension is tapered.